There is a John Munro (indexed Munroe) in the 1841 Census in Blantyre, Lanark. He shows b. Scotland c. 1796 and is a shoemaker. All the entries show as born outside of the County:
John Munroe, 45, shoemaker b. Scotland
Barbara Allan, 40
The rest of the family are showing as MUNSIE
Margt, 15, Cotton P L W
John, 10
Peter, 7
William, 4
Andrew, 2
Regards.
Monica